Mobile communication systems have been developed to provide a voice service while ensuring mobility of users. The mobile communication system has evolved to provide a data service in addition to the voice service. These days, due to explosive growth of traffic, communication resources are easily running short. Also, since demand for higher speed services is great, needs for more advanced mobile communication systems are getting larger.
Requirements for the next-generation mobile communication system largely include accommodation of explosive data traffic, considerable increase of transmission rate for each user, accommodation of the significantly increased number of connected devices, very low end-to-end latency, and high energy efficiency. To meet the requirements, various technologies such as dual connectivity, massive multiple input multiple output (MIMO), in-band full duplex, non-orthogonal multiple access (NOMA), support for super-wideband communication, and device networking are being studied.